CN101689952A - Apparatus and method for removing common phase error in a DVB-T/H receiver - Google Patents
Apparatus and method for removing common phase error in a DVB-T/H receiver Download PDFInfo
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- CN101689952A CN101689952A CN200780053575A CN200780053575A CN101689952A CN 101689952 A CN101689952 A CN 101689952A CN 200780053575 A CN200780053575 A CN 200780053575A CN 200780053575 A CN200780053575 A CN 200780053575A CN 101689952 A CN101689952 A CN 101689952A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/022—Channel estimation of frequency response
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/0224—Channel estimation using sounding signals
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
- H04L25/03006—Arrangements for removing intersymbol interference
- H04L25/03159—Arrangements for removing intersymbol interference operating in the frequency domain
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
- H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
- H04L27/38—Demodulator circuits; Receiver circuits
- H04L27/3845—Demodulator circuits; Receiver circuits using non - coherent demodulation, i.e. not using a phase synchronous carrier
- H04L27/3854—Demodulator circuits; Receiver circuits using non - coherent demodulation, i.e. not using a phase synchronous carrier using a non - coherent carrier, including systems with baseband correction for phase or frequency offset
Abstract
A receiver is a Digital Video Broadcasting-Terrestrial/Handheld (DVB-T/H) receiver. The DVB-T/H receiver comprises a fast fourier transform (FFT) operative on a signal for providing an FFT output signal comprising a number of samples; a spectrum shifter for reordering the samples in the FFT output signal to provide a spectrum shifted signal; and a phase corrector for estimating a phase error fromthe FFT output signal and for correcting a phase of the spectrum shifted signal in accordance with the estimated phase error.
Description
Technical field
The present invention relates in general to communication system, more specifically, relates to wireless system, for example, and terrestrial broadcasting, honeycomb, Wireless Fidelity (Wi-Fi), satellite etc.
Background technology
Digital video broadcast-terrestrial (DVB-T) (for example, is seen ETSI EN 300 744 V1.4.1 (2002-01), Digital Video Broadcasting (DVB); Framing structure, channel coding and modulation for digital terrestrial television (digital video broadcasting (DVB); Digital terrestrial television framing structure, chnnel coding and modulation)) be one of four kinds of Digital Television (DTV) broadcast standard in the world, DVB-H is based on the standard (being also referred to as DVB-T/H herein) of the handheld applications of DVB-T.DVB-T uses OFDM (OFDM) technology, that is, DVB-T uses the form of the multi-carrier transmission of the low symbol rate subcarrier that comprises a plurality of quadratures.
The DVB-T/H receiver comprises antenna and tuner.The tuner that it alignment is tuned to selected frequency range or selected channel provides radio frequency (RF) signal.Tuner carries out down-conversion so that intermediate frequency (IF) signal or baseband signal to be provided to the RF signal that receives in the selected channel, is used for the DVB-T/H receiver and further handles, and for example, recovers TV (TV) program to be shown to the user.Typically, tuner utilizes frequency mixer and voltage controlled oscillator (VCO) to carry out down-conversion.VCO is important element in the tuner.Unfortunately, VCO is the main producer of phase noise (PHN).
Usually, PHN is not a big problem for the analog TV system.Yet for the DTV system that uses OFDM, PHN is more remarkable to the influence of operation of receiver.Particularly, PHN has introduced common phase error (CPE), and it causes the rotation of signal constellation (in digital modulation) (signalconstellation); And generation is superimposed to inter-carrier interference (ICI) item of any interchannel noise.Therefore, the demodulation of the DVB-T signal that receives is subjected to the two interference of CPE and ICI, and therefore the PHN that eliminates in the DVB-T/H receiver is extremely important.
About CPE, the DVB-T receiver can be estimated CPE and by the pilot tone (predetermined subcarrier (that is frequency) with given amplitude and phase place) that use is present in each OFDM symbol it be proofreaied and correct.Two types pilot tone is arranged: scattered pilot (SP) and continuous pilot (CP) in DVB-T.Continuous pilot has the fixed position and is used to eliminate CPE in the OFDM symbol.
Fig. 1 and Fig. 2 show the device of traditional elimination CPE.In DVB-T, two kinds of mode of operations are arranged, the 2K pattern-corresponding to 2048 subcarriers of use, and the 8K pattern-corresponding to using 8192 subcarriers.In this example, suppose that receiver works with the 8K pattern.The work of 2K pattern similarly and herein is not described.The CPE cancellation element of Fig. 1 comprises that fast Fourier transform (FFT) element 105, spectrum shift (spectrumshift) element 110, CPE eliminate element 115 and channel estimation and equalization (CHE) element 120.105 pairs of baseband signals that receive 104 of FFT element are handled.Baseband signal 104 is provided by the tuner that (for example) is tuned to selected RF channel.FFT element 105 with the baseband signal that receives 104 from spatial transform to frequency domain, and FFT output signal 106 offered spectrum shift element 110.Should be noted that 106 expressions of FFT output signal have the complex signal of in-phase component and quadrature component.Typically, FFT element 105 is carried out butterfly well known in the art and is calculated and provide the dateout of rearrangement (8192 duplicate samples in the 8K mode of operation originally).Similarly, spectrum shift element 110 is further handled to rearrange or to be shifted the FFT dateout FFT output signal 106.Particularly, OFDM symbol of spectrum shift element 110 buffering, and with the subcarrier position arrangement for meeting above-mentioned DVB-T standard, and also subcarrier is displaced to [π ,+π] from [0,2 π], with the signal 111 that spectrum shift is provided.CPE eliminates the signal 111 of 115 pairs of spectrum shift of element and handles so that eliminate all CPE (as described below), and CPE correction signal 116 is offered CHE element 120.220 pairs of CPE correction signals 116 of CHE element are handled, and are used for the channel condition information (CSI) that (a) is identified for providing CSI signal 122; (b) baseband signal that receives of equilibrium compensates any transmission-channel distortion, so that equalizing signal 121 to be provided.As known in the art, CSI signal 122 can be used for obtaining the bit metric (not shown in figure 1) used in decoding.Receiver is further handled equalizing signal 121, recovers the content (audio frequency, video etc.) (also not shown among Fig. 1) that wherein transmits with (for example).
Referring now to Fig. 2, the operation that CPE eliminates element 115 will be illustrated in greater detail.CPE eliminates element 115 and comprises: delay buffer 155, CP extractor 160, CP position element 165, CP memory 170, complex conjugate multiplier 175, accumulator 180, phase calculator 185, phase accumulator and sin and cos calculator 190 and circulator (also being called multiplier) 195.The OFDM symbol of a 8K pattern of delay buffer 155 storages, thus provide an OFDM symbol time to postpone, be used for determining the estimation of CPE.For the 8K mode of operation, the size of delay buffer 155 is 8192 * 2 * N bit, and wherein, N is the bit length of data, and the homophase and the quadrature component of 2 expression complex signals.The symbol that postpones is offered circulator 195 with CPE estimated signal 191.Circulator 195 is proofreaied and correct CPE by reverse rotation from the symbol of the delay of delay buffer 155 according to CPE estimated signal 191, so that CPE correction signal 116 to be provided.
Usually, device operation shown in Figure 2 makes according to the auto-correlation of the CP of different time points place appearance, determines CPE estimated signal 191.Particularly, CP extractor 160 extracts CP from the signal 111 of (certain subcarriers that is limited by CP position element 165) spectrum shift.165 storages of CP position element such as the above-mentioned middle CP position that limits of DVB-T standard (for example, seeing the 29th page table 7 of above-mentioned DVB-T standard) that is used for the 8K mode of operation.The CP that extracts is both offered CP memory 170 also offered complex conjugate multiplier 175.Memory 170 also provides the delay of an OFDM symbol.Complex conjugate multiplier 175 will have same frequency but the complex conjugate (that is adjacent OFDM symbol) that appears at the CP at two different time points places multiplies each other.The product that obtains is therefrom all calculated phase error (by phase calculator 185) to each OFDM symbol by average (by accumulator 180).As mentioned above, phase accumulator and sin and cos calculator 190 also add up to the phase error of each OFDM symbol of calculating, and the estimation of definite CPE, so that CPE estimated signal 191 to be provided, CPE estimated signal 191 is offered circulator 195, so that the CPE in the signal is proofreaied and correct.
Summary of the invention
We have recognized that further improvement is possible based on operation and the efficient of the elimination CPE in the receiver of OFDM.Particularly, and according to principle of the present invention, receiver is determined phase error according to the FFT output signal, and according to the signal of the phase error correction spectrum shift of determining.
In exemplary embodiment of the present invention, receiver is the DVB-T/H receiver.The DVB-T/H receiver comprises: fast Fourier transformer (FFT), signal is carried out computing so that the FFT that comprises a plurality of samples to be provided output signal; The spectrum shift device is used for the sample of FFT output signal is resequenced, so that the signal of spectrum shift to be provided; And phase corrector, be used for according to FFT output signal estimating phase error, and be used for phase place according to the signal of the phase error correction spectrum shift of estimating.
In view of above-mentioned, and as it is evident that by reading embodiment other embodiment and feature also are possible and will fall in the concept of the present invention.
Description of drawings
Fig. 1 and Fig. 2 show the elimination of common phase error in the prior art;
Fig. 3 shows the exemplary embodiment of equipment in accordance with the principles of the present invention;
Fig. 4 shows the exemplary embodiment of the part of receiver in accordance with the principles of the present invention;
Fig. 5 shows the exemplary embodiment of phase corrector 215 in accordance with the principles of the present invention;
Fig. 6 to Fig. 14 shows the exemplary frequency spectrum displacement concordance list that is associated with FFT element 205;
Figure 15 and Figure 16 show and continuous pilot (CP) the position table relevant according to the phase corrector 215 of principle of the invention work;
Figure 17 shows the exemplary matlab program that is used for according to table 1 table 3 being converted to table 4; And
Figure 18 and Figure 19 show the exemplary process diagram of using in receiver in accordance with the principles of the present invention.
Embodiment
Except inventive concept, the element shown in the accompanying drawing all is known, and will be not described in detail.For example, except inventive concept, suppose to be familiar with discrete multi-tone (DMT) transmission and (be also referred to as OFDM (OFDM) or sign indicating number OFDM (COFDM) and do not describe in detail in this article.In addition, suppose familiar with television broadcasting, receiver and video coding, and do not describe in detail in this article.For example, except inventive concept, suppose to be familiar with current TV standard and to the suggestion of its proposition, these standards such as NTSC (national television system committee), PAL (line-by-line inversion), SECAM (order transmit colored with storage), ATSC (Advanced Television Systems Committee) (ATSC), digital video broadcasting (DVB) and the 20600-2006 of China Digital TV system (GB) (DMB-ground/hand-held (DVB-T/H)).Further information about DVB-T/H can be at for example ETSI EN 300 744 V1.4.1 (2002-01), Digital VideoBroadcasting (DVB); Framing structure, channel coding and modulationfor digital terrestrial television (digital video broadcasting (DVB); Digital terrestrial television framing structure, chnnel coding and modulation); And ETSI EN 302 304V 1.1.1 (2004-11), Digital Video Broadcasting (DVB); TransmissionSystem for Handheld terminals (DVB-H) (digital video broadcasting (DVB); Find in the handheld terminal transmission system (DVB-H).Equally, except inventive concept, suppose to be familiar with other transmission designs, such as eight grades of vestigial sidebands (8-VSB), quadrature amplitude modulation (qam), and receiver module, such as radio frequency (RF) front end, or receiver portion, such as low noise block, tuner and low-converter; And fast Fourier transform (FFT) element, spectrum shift device, channel condition information (CSI) estimator, equalizer, demodulator, correlator, leak integrators and squarer.In addition, except inventive concept, suppose familiar processing signals, and be not described in this article such as the formation channel condition information.Similarly, except inventive concept, the format and the coding method (such as Motion Picture Experts Group (MPEG)-2 system standard (ISO/IEC 13818-1)) that are used to produce transmission bit stream are known and are not described in this article.Should also be noted that and can use traditional programming technique (such as by the matlab representative) to realize that the present invention conceives, same, this programming technique is not described in this article.In this, the embodiment that describes herein can realize in the analog or digital field.In addition, those skilled in the art will appreciate that some processing can relate to complicated signal path as required.At last, identical reference number is represented similar elements in the accompanying drawing.
Referring now to Fig. 3, show and install 10 exemplary embodiment in accordance with the principles of the present invention.Any platform of device 10 representatives based on processor, for example, PC, server, set-top box, PDA(Personal Digital Assistant), cell phone, mobile digital TV (DTV), DTV etc.In this, device 10 comprises the one or more processors with associative storage (not shown), and comprises receiver 15.Receiver 15 is via antenna (not shown) receiving broadcast signal 1.For example purposes, suppose that broadcast singal 1 represents DVB-T/H service, promptly, the DTV transport stream, this transport stream comprises video, audio frequency and/or the system information that is used at least one TV channel, and broadcast singal 1 uses at least one multi-carrier modulation (such as OFDM (OFDM)) to transmit this information.Yet inventive concept is not limited to this, but can be applicable to handle any receiver based on the signal of OFDM.According to principle of the present invention, receiver 15 according to channel condition information (CSI) to the error correction of signal excute phase, and recovering output signal 16 to be applied to output device 20 from it, this output device can be or can not be the part of device 10, and is shown in dotted line.In the context of this example, output device 20 is to allow the user to watch the display of selected TV program.
Turn to Fig. 4 now, show the exemplary part of receiver 15.Only show that part of relevant of receiver 15 with inventive concept.Except inventive concept, the element shown in Fig. 4 all is known and is not described in this article.In this example, suppose that receiver 15 works with the 2K pattern.The work that should be noted that the 8K pattern similarly is not described in this article equally.Receiver 15 comprises low-converter 200, fast Fourier transform (FFT) element 205, spectrum shift element 210, phase corrector 215 and channel estimation and equalization device (CHE) 220.In addition, receiver 15 is based on the system of processor, and comprises one or more processors and the memory that is associated, as represented with processor 290 shown in the form of frame of broken lines and memory 295 among Fig. 4.In this case, be used for computer program or software that processor 290 carries out and be stored in memory 295.One or more stored program processor controls of processor 290 representative, and they needn't be exclusively used in receiver function, for example, other function that processor 290 can also receiver control 15.For example, if receiver 15 is the parts than bigger device, then processor 290 can be controlled other function of this device.Any storage device of memory 295 representatives, for example, random-access memory (ram), read-only memory (ROM) etc.; It can be positioned at the inside and/or the outside of receiver 15; And can be as required volatibility and/or non-volatile.
Focus onto Fig. 5 now, the figure shows the exemplary embodiment of phase corrector 21 5 in accordance with the principles of the present invention.Phase corrector 215 comprises CP correcting element 305, be shifted CP position element 310, memory 315, complex conjugate multiplier 320, accumulator 325, phase calculator and sin and cos calculator 330 and circulator (or multiplier) 335 in advance.Except inventive concept, the element shown in Fig. 5 all is known and is not described in this article.From the beginning, should be noted that the present invention conceives the fact of having utilized spectrum shift element 21 0 to cushion an OFDM symbol.Particularly, as can be observed from Fig. 5, phase corrector 215 uses FFT output signals 206 to come estimating phase error, and the phase error of the signal 211 of corrected spectrum displacement.Therefore, an advantage of the present invention is: the present invention can with receiver need still less internal memory and the mode of cost still less realize.
About phase error is proofreaied and correct, and as mentioned above, the phase place of the signal 211 of 215 pairs of spectrum shift of phase corrector is proofreaied and correct.Particularly, the signal 211 with spectrum shift is applied to circulator 335 with phase error estimation and phase error signal 331.Circulator 335 comes phase error (for example CPE) is proofreaied and correct according to the signal 211 of phase error estimation and phase error signal 331 by the reverse rotation spectrum shift, with the signal 216 that phasing is provided.Desirable, phase error estimation and phase error signal 331 is proofreaied and correct all phase errors basically, that is, even be not all, at least also be that some phase error is eliminated from this signal by circulator 335.As used herein, any elimination phase error that relates to is meant, even be not to eliminate, at least also is to reduce phase error.
About estimating phase error, and as mentioned above, phase corrector 215 uses 206 pairs of phase errors of FFT output signal to estimate.Yet as previously mentioned, the FFT element 205 of Fig. 4 is carried out butterfly known in the art and is calculated, and the dateout (2048 duplicate samples of 2k mode of operation originally) of rearrangement is provided.Therefore, any use about the CP position of FFT output signal 206 that defines among the DVB-T all needs further adjustment, so that the rearrangement of this FFT is taken into account.Therefore, the pre-displacement of the CP position element 310 storages CP value that is shifted in advance, these are worth shown in the table 4 of Figure 16.These CP values are " pre-displacement ", are meant that this is as (but with respect to the ordering that is provided by FFT element 205) CP position is provided among the DVB-T.Particularly, for such as the FFT by FFT element 205 representative of 2K mode of operation, the spectrum shift concordance list that is associated is known.Table 1 among Fig. 6 to Figure 14 shows the exemplary frequency spectrum displacement concordance list that is used for the 2k mode of operation.For example, for sample index, k, 1≤k≤2048 wherein, Fig. 6 shows 240 spectrum shift frequency values in foremost of 240 the k values in foremost of FFT element 205.Particularly, when k=1, it is 1024 frequency values that relevant spectrum shift index value has; And when k=16, it is 832 frequency values that the spectrum shift index value that is associated has, and when k=240, and it is 884 frequency values that the spectrum shift index value that is associated has, or the like, when k=2048 shown in Figure 14 is 1023 spectrum shift frequency values.Therefore, according to table 1, will be possible as CP displacement to its position in FFT output signal 206 that defines among the DVB-T.This is illustrated in table 2, table 3 and the table 4 of Figure 15 and Figure 16.
The table 2 of Figure 15 only shows the current subcarrier position with 45 CP of 2k pattern work that defines in DVB-T.For example, referring to the 29th page table 7 of above-mentioned DVB-T standard.Therefore, as shown in table 2, a CP occurs as subcarrier value 0, or the like.Yet in DVB-T, although 2048 subcarriers are arranged, it is effectively actual having only 1705 subcarriers.Effectively before the subcarrier 172 invalid subcarriers are being arranged, and effectively after the subcarrier 171 invalid subcarriers are being arranged.This OFDM symbol 81 by Figure 15 (not in scale) illustrates.In this, because phase corrector 215 comes estimating phase error according to FFT output signal 206 rather than according to the signal 211 of spectrum shift, therefore must consider whole 2048 subcarriers.Therefore, must at first convert table 2 to table 3, wherein each value in the table 2 all has been shifted 172.Shown in dotted line 91, when considering invalid subcarrier, the effective subcarrier CP reality that is positioned at 0 place is corresponding to subcarrier 172.According to the value of table 3, and the spectrum shift index value shown in the table 1 among given Fig. 6 to Figure 14, the pre-shift position (being its position in FFT output signal 206) of calculating whole CP now is possible.Result calculated at 45 CP of 2k mode of operation has been shown in the table 4 of Figure 16.For example, the CP that is positioned at subcarrier 976 places is associated with catalogue number(Cat.No.) 63 (since 0), shown in dotted line 92.This can be verified from table 1, and table 1 can be observed from Fig. 6 from k=1, and k=64 is associated with subcarrier 976.Equally, shown in dotted line 93, the CP that is positioned at subcarrier 1141 places be catalogue number(Cat.No.) 744 (also being) since 0 (for example, see Table 1, Fig. 9, k=745).Temporarily turn to Figure 17, the figure shows and be used for table 2 is converted to table 3, form the exemplary matlab program of table 4 then according to table 1 from table 3.Therefore, be shifted CP position element 310 storage in advance as table 4 limited among Figure 16 CP position.
For each CP, the respective sample value of the pre-displacement CP that is associated is offered CP correcting element 305 from memory 310.(should remember that each CP has given amplitude and phase place).Each CP value (for example, phase value) is revised or proofreaied and correct to CP correcting element 305 according to the CSI information that provides from CHE 220 via CSI signal 222.Except inventive concept, CSI information is well known in the art, and this paper is not described.In general, CSI information has been considered each subcarrier reliability when being subjected to the influencing of transmission channel.According to principle of the present invention, consider channel response information by proofreading and correct pre-displacement CP value, then the influence of channel can be eliminated in the processing procedure in phase error and be eliminated, and therefore, it is possible obtaining good estimated performance.CP correcting element 305 offers memory 315 with the CSI-CP sequence 306 that obtains and stores.Complex conjugate multiplier 320 multiplies each other the complex conjugate and the FFT output signal 206 of the CSI-CP sequence (from memory 315) of being stored.At each OFDM symbol the product that obtains is averaged (by accumulator 325).Phase calculator and sin and cos calculator 330 further calculate the estimation of phase error and produce homophase and quadrature value, so that phase error estimation and phase error signal 331 to be provided, phase error estimation and phase error signal 331 is offered circulator 335, so that the phase error in the signal is proofreaied and correct.Should see to draw that the phase error correction element shown in Fig. 5 makes CSI-CP sequence and FFT output signal 206 crosscorrelations (opposite with the autocorrelation technique between the time shift sample of the same signal in the conventional art among Fig. 2).
Turn to Figure 18 and Figure 19 now, show the exemplary process diagram of in the receiver of excute phase error correction in accordance with the principles of the present invention, using.In step 405, receiver carries out down-conversion (for example, the receiver 15 of Fig. 3) with the broadcast singal that receives.In step 410, receiver is according to the phase error in the principle estimation down-conversion signal of the present invention.And in step 415, receiver is proofreaied and correct down-conversion signal, the phase error that is used to estimate.
The flow chart of Figure 19 illustrates in greater detail the step 410 of Figure 18.In step 505, the CP position of receiver (for example, the memory of representing from the element 310 of Fig. 5) the pre-displacement of retrieval.In step 510, receiver utilizes CSI that pre-displacement CP is proofreaied and correct so that CSI-CP to be provided sequence, that is, and and the sequence of the pre-displacement CP value after the correction.In step 515, CSI-CP sequence and FFT output signal (representative down-conversion signal) crosscorrelation, its result is used for determining the estimation of phase error in step 520.
As mentioned above, and according to principle of the present invention, receiver carries out phase error correction according to channel condition information (CSI) to signal (for example, as CPE result).In this, the traditional C PE elimination element 115 than Fig. 2 can obtain at least two advantages.At first, compare, do not need to be used for the individual delays buffer 155 of OFDM symbol with Fig. 2.Therefore, the present invention conceives the remarkable needs that reduce memory, especially for the 8k mode of operation.Secondly, than Fig. 2, do not need the phase accumulator function of element 190.Therefore, the phase error processing has further been simplified in this inventive concept.Yet the present invention design is not limited to this, and those skilled in the art can envision in accordance with the principles of the present invention phase error and eliminate element not utilizing under these benefits situation of (for example, by comprising the OFDM symbol buffer).In addition, should be noted that the present invention conceives is not limited to only one type phase error (such as CPE) be proofreaied and correct.In addition, although should be noted that design of the present invention has been described under the situation of DTV-T broadcast singal, the present invention's design is not limited thereto, but can be applicable to carry out the receiver of other type that OFDM receives, such as software defined radio receiver, DMB-T/H receiver etc.
As mentioned above, aforementioned part has only illustrated principle of the present invention, thereby should be appreciated that those skilled in the art can design the multiple replaceable unit (although clearly not describing in this article) that can realize the principle of the invention, and fall in the spirit and scope of the present invention's design.For example, although be illustrated under the situation of separate functional elements, these function element can realize in one or more integrated circuits (IC).Similarly, although illustrate as independent component, but any one in these elements or all can be (for example in the stored program processor controls, digital signal processor) realizes in that this processor is carried out corresponding to the associated software of (shown in for example Figure 18 to Figure 19 waits) one or more steps etc.In addition, principle of the present invention can be applicable to the communication system of other type, for example, and satellite, Wireless Fidelity (Wi-Fi), honeycomb etc.In fact, this inventive concept also can be applicable to fixing or mobile receiver.Therefore should be appreciated that, can carry out multiple improvement to exemplary embodiment, and under the condition that does not deviate from the spirit and scope of the present invention that are defined by the following claims, can design other device.
Claims (19)
1. method of in receiver, using, described method comprises:
Signal is carried out fast Fourier transform (FFT), so that FFT to be provided output signal;
Described FFT output signal is carried out spectrum shift, so that the signal of spectrum shift to be provided;
Determine phase error according to described FFT output signal; And
According to determined phase error the signal of described spectrum shift is proofreaied and correct, so that the signal of correction to be provided.
2. method according to claim 1 further may further comprise the steps:
Carry out down-conversion to the received signal so that described signal to be provided.
3. method according to claim 1, wherein, described phase error is represented common phase error.
4. method according to claim 1, wherein, described definite step further comprises:
Revise the pre-continuous pilot (CP) that is shifted according to channel condition information (CSI), so that the CP-CSI sequence of pre-displacement to be provided;
Make the CP-CSI sequence crosscorrelation of described FFT output signal and described pre-displacement, so that cross-correlation result to be provided; And
Determine described phase error according to described cross-correlation result.
5. method according to claim 4 further may further comprise the steps:
Signal to described correction is handled, so that described CSI information to be provided.
6. method according to claim 4 further may further comprise the steps:
Signal to described correction carries out equilibrium, to provide balanced signal by the mode that generates CSI information.
7. method according to claim 1, wherein, the step of described correction may further comprise the steps:
Rotate described signal according to determined phase error.
8. equipment comprises:
Fast Fourier transformer (FFT) is used for signal is carried out computing, so that the FFT that comprises a plurality of samples to be provided output signal;
The spectrum shift device is used for a plurality of samples of described FFT output signal are resequenced, so that the signal of spectrum shift to be provided; And
Phase corrector is used for according to described FFT output signal estimating phase error, and is used for according to estimated phase error the phase place of the signal of described spectrum shift being proofreaied and correct.
9. equipment according to claim 8, wherein, described phase error is represented common phase error.
10. equipment according to claim 8, wherein, described phase corrector comprises:
Memory is used for storing the position of continuous pilot (CP) of the pre-displacement of described FFT output signal;
Memory is used for the CP of the pre-displacement of memory modify, and wherein, the CP of the pre-displacement of described modification obtains from the CP of described pre-displacement and channel condition information (CSI); And
Cross correlation is used to estimate described phase error, and wherein, described cross correlation makes the CP and the described FFT output signal crosscorrelation of the pre-displacement of described modification.
11. equipment according to claim 8 further comprises:
Circulator is used for according to estimated phase error the phase place of the signal of described spectrum shift being proofreaied and correct.
12. equipment according to claim 8 further comprises:
Equalizer is used for the signal of the described spectrum shift of having carried out phasing is carried out equilibrium, and is used to provide described CSI.
13. equipment according to claim 8 further comprises:
Low-converter is used for carrying out to the received signal down-conversion, so that described signal to be provided.
14. an equipment comprises:
Low-converter is used to provide down-conversion signal; And
Processor, be used for first signal of the fast Fourier transform of representing described down-conversion signal is carried out computing, with estimating phase error from described first signal, and be used for the phase place of secondary signal being proofreaied and correct according to estimated phase error, wherein, described secondary signal is represented the form of the spectrum shift of described first signal.
15. equipment according to claim 14 further comprises:
Memory is used for storing the position of continuous pilot (CP) of the pre-displacement of described first signal,
Wherein, described processor (a) forms CP corresponding to the modification of the position of being stored according to channel condition information (CSI), and (b) makes the CP of described modification relevant with described first signal cross, to estimate described phase error.
16. equipment according to claim 15, wherein, described processor is handled to determine described CSI information described secondary signal.
17. equipment according to claim 15, wherein, described processor carries out equilibrium in the mode that generates CSI information to described secondary signal.
18. equipment according to claim 14, wherein,
Described processor is by rotating the phase place that described secondary signal is proofreaied and correct described secondary signal according to estimated phase error.
19. equipment according to claim 14, wherein, estimated phase error is represented common phase error.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/CN2007/002033 WO2009003306A1 (en) | 2007-06-29 | 2007-06-29 | Apparatus and method for removing common phase error in a dvb-t/h receiver |
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| Publication Number | Publication Date |
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| CN101689952B CN101689952B (en) | 2013-06-05 |
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| EP (1) | EP2171896A4 (en) |
| JP (1) | JP4961038B2 (en) |
| KR (1) | KR101395686B1 (en) |
| CN (1) | CN101689952B (en) |
| BR (1) | BRPI0721774B1 (en) |
| WO (1) | WO2009003306A1 (en) |
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| CN103703705A (en) * | 2011-04-22 | 2014-04-02 | 索尼公司 | Reception device, reception method, program, and reception system |
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-
2007
- 2007-06-29 CN CN2007800535758A patent/CN101689952B/en active Active
- 2007-06-29 EP EP07721600A patent/EP2171896A4/en not_active Withdrawn
- 2007-06-29 WO PCT/CN2007/002033 patent/WO2009003306A1/en active Application Filing
- 2007-06-29 KR KR1020097027310A patent/KR101395686B1/en active IP Right Grant
- 2007-06-29 US US12/452,407 patent/US8401097B2/en active Active
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103703705A (en) * | 2011-04-22 | 2014-04-02 | 索尼公司 | Reception device, reception method, program, and reception system |
| CN103703705B (en) * | 2011-04-22 | 2017-10-10 | 索尼公司 | Receiving device, method of reseptance and reception system |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2009003306A1 (en) | 2009-01-08 |
| BRPI0721774B1 (en) | 2020-01-28 |
| JP2010532114A (en) | 2010-09-30 |
| US8401097B2 (en) | 2013-03-19 |
| EP2171896A1 (en) | 2010-04-07 |
| JP4961038B2 (en) | 2012-06-27 |
| EP2171896A4 (en) | 2012-06-06 |
| BRPI0721774A2 (en) | 2013-04-02 |
| CN101689952B (en) | 2013-06-05 |
| KR101395686B1 (en) | 2014-05-15 |
| US20100119013A1 (en) | 2010-05-13 |
| KR20100024447A (en) | 2010-03-05 |
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